1. Field of the Invention
This invention relates to a panel structure for plasma display panels.
The present application claims priority from Japanese Applications No. 2003-129831, the disclosures of which are incorporated herein by reference.
2. Description of the Related Art
Surface-discharge-type AC plasma display panels (hereinafter referred to as “PDP”) have recently gained the spotlight as types of large-sized slim color display apparatuses and are becoming increasingly common in homes and the like.
FIG. 1 to FIG. 4 illustrate the structure of a conventional two-electrode surface-discharge-type AC PDP.
FIG. 1 is a perspective view partially showing the panel structure of the conventional PDP. FIG. 2 is a front view of the display surface of the PDP. FIG. 3 is a sectional view taken along the V—V line in FIG. 2. FIG. 4 is a sectional view taken along the W—W line in FIG. 2.
In FIGS. 1 to 4, second electrodes Y each extending in the column direction (the vertical direction in FIG. 2) are arranged regularly at required intervals in the row direction (the right-left direction in FIG. 2) on the rear-facing face of a front glass substrate 1. The second electrodes Y are covered with a first dielectric layer 2 formed on the rear-facing face of the front glass substrate 1.
First electrodes X each extending in the row direction are arranged regularly at required intervals in the column direction on the rear-facing face of the first dielectric layer 2, and covered with a second dielectric layer 3 formed on the rear-facing face of the first dielectric layer 2.
The first electrode X is composed of a first electrode body Xa formed of a strip-shaped metal film extending in the row direction, and first electrode projections Xb formed of a transparent conductive film made of ITO or the like. Each of the first electrode projections Xb extends in the downward direction in FIG. 2 from the mid-position in each section of the first electrode body Xa between the adjacent two second electrodes Y.
The second electrode Y is composed of a second electrode body Ya formed of a strip-shaped metal film extending in the column direction, and second electrode projections Yb formed of a transparent conductive film made of ITO or the like. Each of the second electrode projections Yb extends in the row direction from approximately the mid-position in each section of the second electrode body Ya between the adjacent two first electrodes X, to a position opposite to the first electrode projection Xb when viewed from the front glass substrate 1.
An MgO-made protective layer 4 is formed on the rear-facing face of the second dielectric layer 3.
The front glass substrate 1 is opposite and parallel to a back glass substrate 5 with a discharge space S in between. Strip-shaped partition walls 6 are formed on the inner face of the back glass substrate 5 facing toward the front glass substrate 1. Each of the partition walls 6 extends in the column direction in a position opposite the second electrode body Ya of the second electrode Y.
Phosphor layers 7 are formed individually between the two partition walls 6 on the back glass substrate 5, in other words, in a position opposite the first electrode projections Xb of the first electrodes X and the second electrode projections Yb of the second projection Y when viewed from the front glass substrate 1, in such a way as to cover the face of the back glass substrate 5 and side faces of the partition walls 6.
The colors used for the phosphor layers 7 are the three primary colors red (R), green (G) and blue (B), which are arranged in this order in the row direction.
Inside the discharge space S, discharge cells C are formed in each position opposite the opposed and paired first and second electrode projections Xb and Yb of the first and second electrodes X and Y when viewed from the front glass substrate 1.
The discharge space S is filled with a discharge gas.
In the aforementioned two-electrode-structured PDP, in a reset period, a reset discharge is produced, simultaneously in all discharge cells C, between the first electrode projection Xb of the first electrode X and the second electrode projection Yb of the second electrode Y, to erase the wall charge on the first dielectric layer 2 and the second dielectric layer 3.
Then, in the subsequent addressing period, a scan pulse is sequentially applied to the first electrode X, and a data pulse generated according to the image signal is applied to the second electrode Y. Thereupon, selectively, an addressing discharge is produced between the opposed and paired first and second electrode projections Xb and Yb.
As a result of this addressing discharge, the discharge cells (lighted cells) C having a wall charge generated through the discharge, and the discharge cells (non-lighted cells) C having no wall charge generated are distributed over the panel surface of the PDP in accordance with the image to be generated.
After that, in the subsequent discharge-sustaining emission period, a discharge-sustaining pulse is applied alternately to the first electrode X and the second electrode Y. With every application of the discharge-sustaining pulse, a sustain discharge d (see FIG. 3) is produced between the first and second electrode projections Xb and Yb opposite to each other in each lighted cell.
This sustain discharge d effects the generation of ultraviolet light from the discharge gas sealed in the discharge space S. The ultraviolet light excites the red (R)-, green (G)- and blue (B)-colored phosphor layers 7 facing the lighted cells to allow the phosphor layers 7 to emit visible light for the generation of the image according to the image signal on the panel surface of the PDP.
The conventional panel structure for the PDP as described above is described in Japanese Patent Laid-open Application No. 2001-283735.
This conventional two-electrode-structure PDP has the first electrode X and the second electrode Y formed respectively in the different dielectric layers, namely in the first dielectric layer 2 and the second dielectric layer 3, as is seen clearly from FIG. 3, so as to be positioned individually in different planes from each other in the thickness direction of the PDP. Hence, the thickness of the dielectric layer interposed between the first electrode X and the discharge space at the discharge cell C is different from, i.e. thinner than, the thickness of the dielectric layer interposed between the second electrode Y and the discharge space in the discharge cell C.
For this reason, the first electrode X and the second electrode Y differ in the electric field created in the discharge space at the discharge cell C. As a result, there is a likelihood of the problem of a discharge being produced only in one direction.
Further, a difference is likely to occur between the drive voltages applied to the first electrode X and the second electrode Y, making the discharge characteristics unstable.